In systems for the undersea recovery of oil, it is usual practice to use floating, tower-like structures to conduct drilling necessary to establish the existance of exploitable deposits of hydrocarbons and then to use stationary structures located between the sea bed and the sea surface to achieve the actual hydrocarbon recovery. Such structures, whether they be floating or stationary, entail a series of inconveniencies and perils. The structures are subjected to weather, wind and sea currents, and the transport of crews and materials must be effected on or above the surface of the sea. In addition, the transport of produced hydrocarbons must be effected by means of pipelines or floating loading buoys, thus involving danger of leakages and structural difficulties. It is also essential that any blowout occur in open air such that the flowing of liquid hydrocarbon will accumulate on the sea surface, thereby exposing it to possible ignition which, once started, is very difficult to control.
For the purpose of avoiding the inconveniencies and perils indicated, it has been suggested to arrange drilling and the associated apparatus for developing oil fields in a chamber which is excavated in the sea bed and which communicates with an ashore terminal through a horizontal tunnel. For the purpose of avoiding the occurrence of a blowout, with the inherent dangers to the crew operating the apparatus in the under-sea system, it has been suggested to arrange a separate chamber below the operation chamber accommodating safety valves, tubes and pumps in a distinct drilling mud system, which is to be initiated at the occurrence of such a pipe breakdown which might lead to a blowout. However, such systems are scarcely practicable, partly due to the large quantity of apparatus involved and partly due to the fact that the security obtained is rather restricted, substantially to simple pipe fractures, while other risks of fatal situations are still present.
The present invention is based on a different conception, aiming at a system wherein the damaging effects of a blowout or other accidents which might occur in a submarine drilling and oil recovery system are restricted, i.e., such that escaping hydrocarbons are immediately taken care of and disposed of.